133281931 has 4 divisors (see below), whose sum is σ = 133305912. Its totient is φ = 133257952.

The previous prime is 133281899. The next prime is 133281937. The reversal of 133281931 is 139182331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 139182331 = 41 ⋅3394691.

It is a cyclic number.

It is not a de Polignac number, because 133281931 - 2⁵ = 133281899 is a prime.

It is a super-2 number, since 2×133281931² = 35528146262177522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 133281893 and 133281902.

It is not an unprimeable number, because it can be changed into a prime (133281937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1140 + ... + 16366.

It is an arithmetic number, because the mean of its divisors is an integer number (33326478).

Almost surely, 2^133281931 is an apocalyptic number.

133281931 is a deficient number, since it is larger than the sum of its proper divisors (23981).

133281931 is an equidigital number, since it uses as much as digits as its factorization.

133281931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23980.

The product of its digits is 3888, while the sum is 31.

The square root of 133281931 is about 11544.7793829072. The cubic root of 133281931 is about 510.8072963360.

The spelling of 133281931 in words is "one hundred thirty-three million, two hundred eighty-one thousand, nine hundred thirty-one".